DOS/4GW
From Computer History Wiki
DOS/4GW is a [Dos extender] made popular by Watcom C. It was released by Rational, then Tenberry software. This DOS Extender was largely associated with Doom, and of course the Watcom C compiler.
DOS/4GW allows up to 64MB of memory under the DPMI host.
More information can be found on tenberry.com.